1. Field of the Invention
The present invention relates to an amplifier for amplifying a gradation voltage corresponding to a luminance level of a pixel based on a video signal, and a display driver including the amplifier.
2. Description of the Related Art
A liquid crystal display apparatus, which is an example of display apparatuses, includes a liquid crystal display panel and a display driver for providing voltages based on a video signal to a plurality of data lines formed in the liquid crystal display panel. The display driver includes output amplifiers for amplifying the voltages based on the video signal (see Japanese Patent Application Laid-Open No. 2012-27127, for example).
The output amplifier includes: a differential input stage that receives an inputted signal; a current mirror circuit that generates a current corresponding to a signal generated in the differential input stage; and an output stage that generates an output voltage based on the current generated in the current mirror circuit. The output voltage generated by such an output amplifier is fed back into the differential input stage.
In order to prevent the ringing of the output voltage, which will be generated when the level of the input signal abruptly changes, the above-described output amplifier includes a bias control circuit for increasing a bias current flowing through the output amplifier at the timing when the level of the input signal changes.